1. Field of the Invention
The present invention relates to a method of , and an apparatus for, manufacturing photographic film and photographic film cassettes. More particularly, the present invention relates to a method of, and an apparatus for, manufacturing a photographic filmstrip having a predetermined length and perforations, and data magnetically recorded thereon. The present invention also relates to a method of, and an apparatus for, cutting and winding the photographic filmstrip. The present disclosure is based on the disclosures of Japanese Patent Appln. Nos. 4-206653, 4-272987 and 4-326982 filed Aug. 3, Oct. 12 and Dec. 7, 1992 respectively, which disclosures are incorporated herein by reference.
2. Description of the Related Art
A photographic film cassette is constituted of a cassette shell, and a roll of photographic film accommodated in the cassette shell in light-tight fashion. 35 mm (135 type) film cassettes or cartridges are well known.
Generally, a photographic filmstrip to be loaded in a cassette shell is manufactured by the following process. First, a sheet of film having a photosensitive emulsion layer applied on one surface thereon is slit to a predetermined width, and a consequent long strip of photographic film is wound about a rotary shaft, which is driven by a motor, into a roll. The long film is drawn from the roll and transported at a constant speed along a manufactured line. In the manufacturing line, a perforator forms perforations in the film at regular intervals. The long film having the perforations formed therethrough is then cut to predetermined lengths to form individual filmstrips.
An automatic film cutting and winding apparatus which sequentially performs the process of drawing the long film by a predetermined length from the roll, cutting the long film at the predetermined length from the roll into individual filmstrips, transferring the individual filmstrip from the cutting position to a securing position, securing the filmstrip to a spool, and winding the filmstrip on the spool, is well known.
Such an automatic film cutting and winding apparatus is disclosed, for example, in Japanese Patent Publication 63-4036, JPA 2-222946 and JPA 3-182451. In the apparatus disclosed in Japanese Patent Publication 63-4036, there is a film feeding and measuring section, a cutting section, an intermediate holder for storing a length of the long film that is approximately equal to the predetermined length of the individual filmstrip, a feed roller section for feeding the filmstrip out of the intermediate holder, and a film securing section, sequentially disposed in that order along a film transport path for feeding the long film from the roll toward the spool. The transient stock in the intermediate holder contributes to shortening a stand-by period in each of the above sections.
In the apparatus disclosed in JPA 2-222946, a film feeding and measuring section, a cutting section, a feed roller section and a film securing section are sequentially disposed on the film transport path in order from the roll, to feed a filmstrip cut from the long film to a spool and secure the filmstrip to the spool. Thereafter, the feed roller section releases the remaining portion of the filmstrip therefrom, and the filmstrip is wound onto the spool.
The most popular 135 type photographic film cassette has a cassette shell constructed of cylindrical barrel made of sheet metal and a pair of caps attached to opposite ends of the barrel. A spool with a photographic film wound thereon is loaded in the cassette shell. According to a method as known from Japanese Patent Publication 2-691, the photographic film is wound on the spool, and then subsequently wrapped with the barrel and the caps in a darkroom. Also a method for assembling such a conventional film cassette is known from Japanese Patent Publication 60-48748 wherein a temporary assembled cassette shell is partly disassembled in a film loading section disposed in a darkroom, to insert the spool with a film wound thereon into the cassette shell. Thereafter, the cassette shell is reassembled.
Furthermore, a photographic film cassette of a leader advancing type is disclosed, for example, in U.S. Pat. Nos. 4,834,306 and 4,846,418, and JPA 3-37645, wherein a cassette shell is constructed of resin molded products and a leading end of a filmstrip wound on a spool can be advanced to the outside of the cassette shell by rotating the spool in an unwinding direction. Because the leading end of the filmstrip is located inside the cassette shell not only after exposure but also before loading of this type of film cassette, light-shielding of the contained filmstrip is improved, and handling of the film cassette, during the loading and the removal thereof is easier as compared with conventional 135 type film cassettes.
Recently, a photographic film has been disclosed in U.S. Pat. Nos. 4,860,037 and 4,864,332, on which film data specific to the photographic film is magnetically recorded. The film data represents, for example, an ID code, a lot number and a film speed of the film, as well as the number of available frames in the film. The data is read by an appropriate device incorporated in a camera when the photographic film is loaded in the camera. Based on the data, a suitable photography mode of the camera is automatically selected, for example, to facilitate taking a high quality photograph.
When finishing the photographic film in a photo-lab, it is necessary to always correlate the respective photographic films with the customers throughout the photo-finishing process. Therefore, data usable for such a correlation is also recorded on the photographic film. Japanese Patent Publication 3-2905 discloses a photographic filmstrip having discrimination data recorded in the vicinity of a perforation in associated with an exposure position in which an image frame is to be exposed. The discrimination data is binary data representing numerical values specific to each individual filmstrip, such as slit data, a supplementary number, etc. And the discrimination data is magnetically recorded and/or photographically recorded as a latent bar code image or the like.
In order to record such magnetic data on the photographic filmstrip, a magnetic recording layer is provided in a predetermined position on the long film, on a side thereof which is opposite from the photosensitive emulsion layer, before the long film is wound in a roll.
However, when recording data on the magnetic recording layer, it has been very difficult to precisely position the data in correspondence with each image frame exposure position on the film, because the long film is transported at a very high speed during the film manufacturing, for example, at a speed of several tens of the ordinary film advancing speed in cameras, to increase production efficiency. Besides, it is impossible to exactly read the magnetic data from the photographic film unless each recording position has a definite positional relation to the image frame exposure position which is designated by a perforation or the like. Data reading is necessary during manufacturing, for checking if the data has been properly recorded on the magnetic recording layer.
When securing a first end of the filmstrip, it is necessary to guide the first end into an engaging portion of the spool with accuracy, and protect the filmstrip from being scratched or blushed during the guiding. Such scratching or blushing may result in lowering the quality of the filmstrip to a certain degree.
In spite of this fact, conventional automatic film cutting and winding apparatus guide the filmstrip through a relatively long distance toward the spool. That is, the filmstrip is transported in the same direction as in the measuring and cutting process toward the spool. Therefore, the first end to be secured to the spool is the forward end in the transporting direction, and the securing position, where the first end is secured to the spool, is spaced apart from the cutting position of the long film, by at least a distance corresponding to the length of the individual filmstrip.
As a result, the first end cannot always be accurately positioned, because of shrinkage or curling of the filmstrip, variance in the transport amount of the filmstrip, and also fluctuation of curvature of the filmstrip during the slitting operation. Therefore, it has been very difficult to quickly and precisely guide and secure the first end of the filmstrip to the spool without scratching and blushing thereof. This hinders rapid manufacturing of the film cassette. This problem is especially serious because photographic films are being manufactured thinner and thinner in the interest of minimizing materials and lightening cameras.
In the above-described leader advance type photographic film cassette, it is necessary, for permitting the film advancing operation, to prevent loosening of the roll of the photographic film wound on the spool when the spool is rotated in the unwinding direction. For this purpose, a photographic film cassette wherein flanges, which confine the opposite sides of the film roll on the spool, are formed from relatively soft material and/or formed separately from the spool core is known. When the spool is mounted in the cassette shell, the flanges are pressed against the opposite sides of the film roll by confining members formed integrally inside the cassette shell. Thereby, the film roll is tightly held by the flanges at opposite sides thereof and thus is prevented from loosening.
When manufacturing such a film cassette, if the so photographic film is first wound on the spool having the soft or separate flanges thereon, and thereafter the spool is mounted in the cassette shell, the flanges can be deformed or damaged by the confining members during the mounting of the spool in the cassette shell or during closing of the cassette shell. This is because the position of the flanges is unstable when not pressed by the confining members. For the same reason, the flanges are frequently not properly positioned inside the confining member in conventional manufacturing processes.
The present invention is directed to solving the above-described problems and thus an object of the present invention is to provide a method of, and an apparatus for, manufacturing a photographic film having a magnetic recording layer, wherein data can be magnetically recorded exactly in proper position relative to each image frame exposure position and/or relative to either end of each individual filmstrip.
Another object of the present invention is to provide a method of, and an apparatus for, manufacturing a photographic film cassette, wherein the positioning of the photographic filmstrip can be performed with accuracy when securing the filmstrip to the spool.
A further object of the present invention is to provide a method of, and an apparatus for, manufacturing a photographic film cassette, which makes it possible to reliably wind the filmstrip into is the cassette shell in the manufacturing process even when the spool has soft flanges or when the cassette shell and/or the flanges are separate parts from the spool core.